The carrier aggregation (CA) technology, which is a technology which improves a data transmission rate by combining two or more component carriers and transmitting the combined component carriers in broadband, has been introduced to high speed packet access (HSPA), long-term evolution (LTE), etc. of 3rd generation part nership project (3GPP) corresponding to the cellular mobile communication standard. The CA technology can effectively increase a data transmission rate by reusing the existing LTE system in an environment in which it is difficult for mobile communication service providers to retain bands continuing for 20 MHz or more, can be flexibly installed, can be compatible with the existing technology, and can operate a different network for each carrier wave, thereby implementing a heterogeneous network. However, since coverage of a cell for each carrier wave is different due to a radio property difference between frequencies or use of different antennas, a cell having the best channel environment for each carrier wave at a location of a user may belong to different evolved node Bs (eNBs). The inter-cell CA technology, which aggregates carrier waves belonging to different eNBs, is called the inter-site CA technology.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.